Intrinsify natural word size typed array getters on IA32 and X64

runtime/vm/intrinsifier_ia32.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // The intrinsic code below is executed before a method has built its frame.
 // The return address is on the stack and the arguments below it.
 // Registers EDX (arguments descriptor) and ECX (function) must be preserved.
 // Each intrinsification method returns true if the corresponding
 // Dart method was intrinsified.
 
@@ skipping 546 matching lines @@
                               TIMES_1,
                               Uint16Array::data_offset()));
   __ SmiTag(EAX);
   __ ret();
   __ Bind(&fall_through);
   return false;
 }
 
 
 bool Intrinsifier::Int32Array_getIndexed(Assembler* assembler) {
+  Label fall_through;
+  TestByteArrayIndex(assembler, &fall_through);
+  __ movl(EAX, FieldAddress(EAX,
+                            EBX,
+                            TIMES_2,
+                            Int32Array::data_offset()));
+  // Copy EBX into EAX.
+  // We destroy EBX while testing if EAX can fit inside a Smi.
+  __ movl(EBX, EAX);
+  // Verify that the signed value in EBX can be stored in a Smi.

[srdjan, 2012/10/12 22:52:48]

Quicker way is to test with:

        __ testl(EAX, Immediate(0xc0000000));
        __ j(negative, &fall_through);

See DoubleToInt.

[Florian Schneider, 2012/10/15 14:29:17]

For signed ints it should be 

__ cmpl(EAX, Immediate(0xc0000000));

I'm fine with either version (shl or cmpl) here, since we can afford to use a
temp register. 

+  __ shll(EBX, Immediate(0x1));
+  __ j(OVERFLOW, &fall_through, Assembler::kNearJump);  // Won't fit Smi.
+  __ SmiTag(EAX);
+  __ ret();
+  __ Bind(&fall_through);
   return false;
 }
 
 
 bool Intrinsifier::Uint32Array_getIndexed(Assembler* assembler) {
+  Label fall_through;
+  TestByteArrayIndex(assembler, &fall_through);
+  __ movl(EAX, FieldAddress(EAX,
+                            EBX,
+                            TIMES_2,
+                            Uint32Array::data_offset()));
+  // Copy EBX into EAX.
+  // We destroy EBX while testing if EAX can fit inside a Smi.
+  __ movl(EBX, EAX);
+    // Verify that the unsigned value in EAX can be stored in a Smi.

[cshapiro, 2012/10/12 22:33:52]

Indentation...

+  __ shrl(EBX, Immediate(30));

[cshapiro, 2012/10/12 22:33:52]

Please use the named constant kSmiBits instead of the number 30.

+  __ j(NOT_ZERO, &fall_through, Assembler::kNearJump);  // Won't fit Smi.

[srdjan, 2012/10/12 22:52:48]

I believe quicker test for unsigned is:

__ testl(EAX, Immediate(0xc0000000));

+  __ SmiTag(EAX);
+  __ ret();
+  __ Bind(&fall_through);
   return false;
 }
 
+
+bool Intrinsifier::Int64Array_getIndexed(Assembler* assembler) {

[srdjan, 2012/10/12 22:52:48]

You could add here code that checks if the result fits into Smi and return Smi
if so.

+  return false;
+}
+
+
+bool Intrinsifier::Uint64Array_getIndexed(Assembler* assembler) {
+  return false;
+}
+
 
 bool Intrinsifier::Float32Array_getIndexed(Assembler* assembler) {
   Label fall_through;
   TestByteArrayIndex(assembler, &fall_through);
   // After TestByteArrayIndex:
   // * EAX has the base address of the byte array.
   // * EBX has the index into the array.
   // EBX contains the SMI index which is shifted left by 1.
   // This shift means we only multiply the index by 2 not 4 (sizeof float).
   // Load single precision float into XMM7.
@@ skipping 961 matching lines @@
   __ Bind(&is_true);
   __ LoadObject(EAX, bool_true);
   __ ret();
   return true;
 }
 
 #undef __
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32